package socket;

import java.io.*;
import java.net.ServerSocket;
import java.net.Socket;
import java.nio.charset.StandardCharsets;
import java.util.ArrayList;
import java.util.List;

/**
 * 聊天服务端
 */
public class Server{
    private ServerSocket serverSocket;
    private List<PrintWriter> allOut = new ArrayList<>();
    public Server() {
            try {
                System.out.println("正在启动服务端");
                serverSocket = new ServerSocket(8105);
                System.out.println("服务端启动完毕!");
            } catch (IOException e) {
                e.printStackTrace();
            }
    }

    public void start(){
        try {
            while (true){
                System.out.println("等待客户端连接");
                Socket socket = serverSocket.accept();
                System.out.println("一个客户端连接了");

                ClientHandler handler = new ClientHandler(socket);
                Thread t = new Thread(handler);
                t.start();
                System.out.println("连接成功");
            }
        }catch (IOException e){
            e.printStackTrace();
        }
    }


    private class ClientHandler implements Runnable{
        private Socket socket;
        private String host;//记录该客户端的IP地址
        public ClientHandler(Socket socket) {
            this.socket = socket;
            host = socket.getInetAddress().getHostAddress();
        }

        @Override
        public void run() {
            PrintWriter pw = null;
            try {

                InputStream in = socket.getInputStream();
                InputStreamReader isr = new InputStreamReader(in, StandardCharsets.UTF_8);
                BufferedReader br =new BufferedReader(isr);

                OutputStream out = socket.getOutputStream();
                OutputStreamWriter osw = new OutputStreamWriter(out,StandardCharsets.UTF_8);
                BufferedWriter bw = new BufferedWriter(osw);

                pw = new PrintWriter(bw,true);
                synchronized (allOut){
                    allOut.add(pw);
                }
                System.out.println(host+"上线了，当前在线人数："+allOut.size());
                String message;
                while ((message = br.readLine())!=null){
                    System.out.println(host+"说："+message);

                    //将消息回复给所有客户端
                    synchronized (allOut){
                        for(PrintWriter o:allOut){
                            o.println(host+"说："+message);
                        }
                    }
                }
            } catch (IOException e) {
                e.printStackTrace();
            }finally {
                synchronized (allOut){
                    allOut.remove(pw);
                }
                System.out.println(host+"下线了，当前在线人数："+allOut.size());
                try {
                    socket.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
    }
    public static void main(String[] args) {
        Server server = new Server();
        server.start();
    }
}
